I have 6to6 capability at my house, yet I had noticed the lynch pin in fast 6to6 browsing in local dns resolution. I have an Airport Extreme, but it refuses to hand out public DNS servers which I put it in, and it runs its own version of the dscaching daemon built into OSX. This daemon in OSX works as intended, but on the ABES 6to6 resolution can take over 15 seconds. Doing directly lookups by forcing external native v4 and v6 DNS servers in my Mac's DNS server configuration (airport in this case), eliminates the problem.
All the Googling I have done shows there is no way to force the ABES to give out designated DNS servers via DHCP and for it NOT to handle DHCP (but to do 4to6 and 4to4 NAT). This is a pitty and something Apple should address, or get its resolver more IPv6 savvy.